This invention relates to a slitting apparatus for slitting a long-sized sheet, such as a film, paper and a processed sheet into a plurality of strips of any desired width accurately, using a plurality of blades.
In a conventional slitter for long-sized sheets, slitting such a sheet to any desired width is carried out by moving a plurality of blades automatically. To be more specific, the known slitters include a shaft-inserted type in which a plurality of blades are fitted over a common shaft as disclosed in, for example, Japanese Patent Application Laid-Open Publication No. 201896/1985, and another type known as a separate holder type in which a plurality of blades are attached to their respective holders, each of which is provided with an operating means for the corresponding blade.
In the above-mentioned shaft-inserted type, the intervals at which the blades may be disposed can be set smaller, so that a sheet can be slit into strips having a smaller width. However, it requires that the blades not actually being used be shifted to both end portions of the shaft. Shifting the blades in this manner takes considerable time. In addition, since the shaft is long, flexure thereof occurs during a slitting operation which can cause the blades to warp and/or be misaligned.
In the above-mentioned separate holder type, flexure of the shaft does not occur. However, each holder holding a blade must include a cylinder for swinging the blade and a motor for laterally moving the blade itself so that the holder is relatively larger-sized and, consequently, spacing between two adjacent blades has to be made larger making it difficult to slit the sheet into strips having a small width.
In both of these types of slitters, the cutting blades consist of a plurality of laterally stationary blades adapted to be rotated at preset positions and at least one laterally movable blade adapted to rotate in slidable contact with a suitable stationary blade. When the stationary blade and the movable blade are brought into slidable contact with each other, a lateral load is applied thereto, so that the movable blade shifts in some cases from a set position at which the movable blade is supposed to remain set. Since the accuracy of setting the movable blade in a predetermined position depends upon how accurately a device for moving the blade can control moving and stopping the blade, a highly accurate blade moving device is required. When such a blade moving device gets out of order, it is not easy to move and set the blade to the predetermined position.
An object of the present invention is therefore, to provide a "separate holder" type slitter arranged to enable cutting of a long-sized sheet into strips having a small width, permit the movable blade to be automatically moved to and set at the predetermined position in a short period of time and further allow the movable blade to be positioned in place even manually, thereby eliminating the above-noted inconveniences.